Synthesis, Characterization, Free-radical Scavenging Capacity and Antioxidant Activity of Novel Series of Hydrazone, 1,3,4-oxadiazole and 1,2,4-triazole Derived from 3,5-dimethyl-1H-pyrazole

Background: Pyrazole is an important class of heterocyclic compound, has been shown to exhibit diverse biological and pharmacological activities such as anti-inflammatory, anti-cancer, antioxidant, etc. Methods: In this study, a series of novel 3,5-dimethyl-1H-pyrazole derivatives containing hydrazine 4a-l have been synthesized via the reaction of the 2-(3,5-dimethyl-1H-pyrazol-1-yl)acetohydrazide. All synthesized compounds have been tested for their in vitro antioxidant activities via utilization of 1,1-biphenyl-2-picrylhydrazyl (DPPH) as a free radical scavenging reagent. Results: The data reported herein indicates that compound 4k showed potential radical scavenging capacity and compounds 4f and 4g exhibited best activity for the iron binding while comparing with positive controls. Conclusion: Good activity was noted for some compounds. In particular, compound 4k showed the highest antioxidant activity with IC50 values of 22.79 ± 3.64 and 1.35 ± 0.66 μg/mL in the DPPH and ABTS tests, respectively.